Games were never live on TV in the 60s and early 70s, they were replayed on Saturday night. There were 6 games a week and about an hour and a half on the replay, including ads. Usually, that meant about a quarter or the main game, maybe 20 minutes of the second. Generally a third game got a highlights package.
The hour and a half format still applied to the finals, so only a bit over half the game was replayed.
The Grand Final was replayed in its entirety. What a treat that was! Can’t remember if they showed ads, probably only at the breaks.